This invention relates generally to semiconductor technology and more particularly to a method of forming conducting diffusion barriers for semiconductor devices.
Diffusion barriers are commonly used in integrated circuit (IC) fabrication to prevent interdiffusion of metals. For example, a TiN film is used to prevent diffusion of Al into Si at contact regions and along metal lines. As the dimensions of ICs, particularly contact regions and metal lines, continue to shrink, the requirements for the conducting barrier also become more stringent. Thinner barriers are required without substantially increasing resistivity. Barriers also need to be more resistant to diffusion of various new metals, which are being introduced into production processes. One of the metals that is being introduced is copper. Although few diffusion barriers materials effectively block the diffusion of copper, metal nitride and silicon nitride have been shown to act as good barriers against copper diffusion.
To produce effective conductive diffusion barriers, the barriers should preferably act to prevent the diffusion of metals into adjacent structures while simultaneously acting as adequate conductors. The conductive diffusion barrier should provide a suitable balance between its diffusion barrier properties and its conductive properties.
It would be advantageous if a conductive diffusion barrier were available that acted as a good barrier against copper, or other metal, while acting as an adequate conductor.
It would be advantageous if a method of forming a diffusion barrier with the desired characteristics could be provided.